Kombucha: Myths vs. Truths

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top view of kombucha brewing jar with scoby at the top

“Everything has beauty, but not everyone sees it.”
~ Confucius

What Is That Thing?

It’s a SCOBY (Symbiotic Culture of Bacteria and Yeast), a term coined by kombucha enthusiast Len Porzio in the mid-1990’s. It may not look appetizing, but it creates a very popular fermented beverage that goes for $4 a bottle in the health food stores. Luckily, you can make it very inexpensively at home. You just need 6 simple ingredients: a SCOBY like the one pictured above, tea, sugar, clean water, a warm place, and time. The final product contains a blend of beneficial bacteria and yeast (probiotics) as well as certain acids and enzymes that aid digestion, detoxify the body, and promote health. However, with popularity sometimes comes infamy, and a number of myths have cropped up surrounding kombucha over the years. Let’s separate the myths from the truths.

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Kombucha History & Science

Kombucha has been around for thousands of years, believed to have originated in China, traveled throughout Asia and Russia and eventually became a health craze in the US over the past two decades. Legend has it that it was named after a Korean physician Kombu who healed the Japanese Emperor Inyko with the tea, and the tea was then named after him: “Kombu” + “cha” (which means tea.)

The science of fermentation is one practiced in homes, rather than laboratories, and for that reason it has an air of mystery. These living foods change from batch to batch, and since they can’t be patented or highly controlled,  there’s no real incentive for the science community to spend resources in research. Therefore, health claims tend to be anecdotal, and certain assumptions about the “science” behind the process get spread with no real evidence to support those assumptions. We know fermented foods are powerful in their ability to support a healthy body, and restore balance to an unhealthy one. We don’t really know the fine details of how this occurs.

Well, Michael Roussin, a kombucha lover, decided he wanted to know what exactly was in this drink that made him feel so good. With the help of a professional lab, he spent 18 months testing 1103 samples of kombucha, from batches all over North America and parts of Europe, with different teas, sugars, temperatures and brewing times, and he discovered some surprising things. Here are some highlights from that report:

Busting the Myths

  • Although kombucha is made with caffeinated tea, by the end of the fermentation cycle, none remains. MYTH. Roussin found that the caffeine content doesn’t reduce at all. This myth might have started because only 6-8 teabags are used to brew a gallon of kombucha tea, which is half the strength of a normal cup of tea. The good news is that kombucha doesn’t need caffeine to thrive. If you want to remove even more of the caffeine, simply pre-steep the tea bags for 30 seconds and throw that water away. Then steep these teabags again in fresh hot water, for the kombucha brew. The majority of the caffeine is dispersed in the pre-steeping. Update: You cannot decaffeinate tea at home. Thanks to Mari in the comments below for busting the myth of pre-steeping tea to remove caffeine. Lab testing shows this eliminates only a small amount of caffeine. If you can’t have caffeine, buy tea that has been decaffeinated by the CO2 method (a healthier choice, compared to the more common chemical decaffeination.)
  • Although kombucha is made with sugar, by the end of the fermentation cycle, none remains. MYTH. There will always be a little sugar remaining, and the amount depends on how long the tea is fermented. Generally, people brew the tea according to their taste. A 5-day brew is going to have a high quantity of sugar remaining. A 30-day brew is going to have very little remaining (yet still some). Most people brew the tea for 7-12 days, when it has a tangy sour flavor with a touch of sweetness remaining; on average, the amount of sugar at this point is 16 grams per 8 oz. cup. This is equal to 4 teaspoons of sugar. You could brew the full 30 days to minimize the sugar, but at that point, the drink is so sour, people usually add juice to make it palatable. If you do this, you’re going to get 12-20 grams of sugar from the juice. This is why many people call it a healthy soda-pop. The “healthy” part comes from the  probiotics and beneficial acids it contains, and rest assured the sugar content is much lower than regular soda. You may feel tempted to try to make your kombucha with less sugar or no sugar at all, but sugar is the food your SCOBY needs to create the probiotics and acids you seek. It will become malnourished and eventually die without it. If you want to know the sugar content of your home brew, you can use sugar test strips. Update: Silvia (in the comments below) did the math and noted that 16 grams per cup is the amount of sugar added when you begin the kombucha brew, so how is it possible that it’s still that concentrated at the 7-15 day mark? Here’s why: In the first stage of fermentation, the yeast uses the minerals from the tea to produce enzymes that separate sugar into glucose and fructose. At the 7-day mark, that’s as far as the process has gone. The sugar is easier to digest, but hasn’t yet diminished in concentration. By the 15-day mark, it is just starting to eat/diminish the sugar content (3.3 teaspoons of sugar per cup remaining at that point.) The sour flavor comes from the acids that are forming, but that sweet tone is still the sugar, unless you brew it a full 30 days. A study done by Cornell University confirmed these results.
  • Kombucha is rich in B vitamins. MYTH. Although it does contain these vitamins, the amounts are so small they are almost immeasurable. This was confirmed by the International Journal of Food Science and Technology.
  • Kombucha is rich in glucuronic acid, a powerful detoxifier of the liver. UPDATE: UNDECIDED. Rouissin found no glucuronic acid in  kombucha. Ironically, he began his experiments intending to prove otherwise. He read a book by Harald Tietze in 1995, who said no reputable lab had ever found glucuronic acid in kombucha, so Roussin hired a reputable lab to prove him wrong. When he confirmed its absence instead, that got him curious about the other assumptions people had about kombucha, and his experiments continued. While he didn’t find glucuronic acid, he did find a different acid that is a synergist. Glucuronic acid is made naturally by the liver and works by binding to a toxic molecule and carrying it out of the body. Rouissin believes this synergist helps our body do its job. Update: Some recent studies report finding glucuronic acid in kombucha. They say Rouissin’s lab wasn’t equipped well enough to identify it. Roussin says they are mis-identifying keto-gluconic acid (the synergist) as glucuronic acid, a common mistake. Who is right? We don’t know. But here’s my thought – does it even matter? Everyone agrees that kombucha helps our bodies detoxify. They’re just disagreeing on a name.
  • Kombucha contains hyaluronic acid and glucosamine, which is why it’s so effective in relieving joint pain. MYTH. Kombucha contains neither of these compounds. However, it does seem to have a positive effect on the joints. Roussin’s theory is that it contains the building blocks for these compounds.
  • Kombucha contains over 50 different kinds of probiotics, organic enzymes, amino acids and vitamins. MYTH. Every batch of kombucha is different. The only things every batch contains are: (1) at least one beneficial yeast, (2) acetobacter (the beneficial bacteria in the SCOBY), (3) gluconic acid (a pH regulator) – note: this is not the same thing as glucuronic acid referenced above, and (4) acetic acid (an anti-microbial acid, which also stabilizes blood sugar) . Most batches of kombucha will also contain an analgesic (pain reliever), an anti-arthritic compound, an anti-spasmodic compound, a liver-protective compound, and several anti-bacterial compounds. The blend varies from batch to batch. See why this elixir can’t be patented? It embodies change.
  • Kombucha can cure everything from arthritis to gout to HIV to cancer. MYTH. As Hannah Crum of Kombucha Kamp says, “Kombucha is not a panacea – it doesn’t cure anything! It brings the body back into balance so that it may heal itself naturally. That is how it is able to do so much.” Results vary from person to person. Many people do say it helps their joint pain, keeps them from getting sick, gives them energy, aids their digestion, clears their sinuses, reduces their blood pressure, clears their eczema, alleviates their headaches, and the list goes on. Then there are other people who say they enjoy the taste, but don’t really notice any effect. And still others who have a negative response to kombucha. The only way to know what it can do for you, is to try it.
  • Kombucha is dangerous and has been linked to deaths. MYTH. This one is repeated a lot, and it usually starts with a sentence like this: “There is no scientific evidence that kombucha promotes health, just anecdotal reports. However, it has been linked to both illness and death.” (With never an acknowledgement that the last sentence is an anecdotal report, and there’s no scientific evidence that kombucha is harmful.) Let’s clear up that report, though, because it’s scary. Fermentation expert Sandor Ellix Katz sums it up nicely: “In 1995 the US Centers for Disease Control (CDC) publication Morbidity and Mortality Weekly Report ran a story headlined, ‘Unexplained Severe Illness Possibly Associated with Consumption of Kombucha Tea,’ with possibly being the operative word. In two separate incidents, weeks apart, two women in Iowa had very different unexplained acute health episodes. One of them died. Both drank kombucha daily and made it from the same original SCOBY. The Iowa Department of Public Health immediately issued a warning to stop drinking kombucha ‘until the role of the tea in the two cases of illness has been evaluated fully.’ But they were never able to explain how kombucha may have been related to the illnesses, and 115 other people were identified who drank kombucha from the same mother without problems. When the mothers and the kombucha that possibly made the women sick were subjected to microbial analysis, ‘no known human pathogens or toxin-producing organisms were identified.'”
  • Kombucha is an alcoholic drink. TRUE. However, it’s a very small amount, usually between .5 and 3%, depending on length of fermentation. (Beer contains 4-6%.) Single fermentation home brews of kombucha usually contain only .5% alcohol. If you do a second fermentation in a bottle, to flavor it and increase the carbonation, the alcohol content will increase slightly. Store bought brands were found to contain more, because the product is still fermenting in the bottle, and a long time can pass between bottling and purchase. For this reason, kombucha was temporarily pulled from store shelves in 2010, while the federal alcohol trade bureau tested numerous samples and developed guidelines for kombucha manufacturers. Now, all store bought brands are supposed to have taken steps to prevent fermentation from continuing in the bottle. Sadly, this often means pasteurization, which limits the benefits of the drink.
  • If you ferment more than one kind of food or beverage (sauerkraut, kefir, kombucha, etc.) you need to keep them away from each other, for fear of cross-contamination: MYTH. Sandor Ellix Katz addressed this in his book, The Art of Fermentation: “While different cultures may subtly influence one another through the air over time, typically this is not an issue….Betty Stechmeyer, who co-founded a starter culture business, GEM cultures, with her late husband Gordon and spent 30 years growing and selling fermentation starters, reports that for all those years she propagated several different sourdoughs, several different milk cultures, tempeh starter and more, in one 12×12 foot kitchen. ‘Pretty primitive and simple, eh?’ She never experienced cross-contamination. I cannot guarantee that cross-contamination among cultures is impossible, but it is not a likely occurrence, and I encourage enthusiastic experimentalists to ferment to your heart’s content without worry.”
  • Kombucha can make you feel worse. TRUE. While most people feel benefits from drinking kombucha, some people’s symptoms worsen. There are a few potential reasons for this: (1) Healing Crisis: Dr. Natasha Campbell-McBride, author of the GAPS Diet, says: “Apart from good bacteria a healthy body is populated by beneficial yeasts which normally protect the person from pathogenic (bad) yeasts, such as candida albicans. Kefir (and kombucha) contain these beneficial yeasts (as well as the beneficial bacteria) which help to take pathogenic yeasts under control.”  However, healing crises shouldn’t last more than a few days. (2) Histamine or Yeast Intolerance: Fermented foods contain beneficial bacteria which improve the health of most people, with the exception of those who are yeast or histamine intolerant. In those cases, negative symptoms from drinking kombucha don’t improve with time, like they do with a healing crisis. So what do you do if you feel like kombucha is making you feel worse? First, lower the amount of kombucha you are drinking, and only increase as your body is able to handle it without discomfort. If you are experiencing a healing crisis, lower doses should slow down the die-off reaction and alleviate your symptoms. If you continue to have discomfort at small doses, stop drinking it altogether and try again in 6 months. (Food intolerances often disappear as we heal.)
  • FAQ: What about GT? Since writing this post, I have gotten numerous emails and blog comments asking about GT’s kombucha label, which seems to contradict this article. So the question people ask is this: who is right? First let me say I’m grateful that GT continued to make raw kombucha when many other brands went 100% pasteurized. It means that when I travel, I still have access to the real thing. However, that doesn’t mean I believe all their label claims. Inaccurate labels are incredibly common. The FDA simply doesn’t have the manpower to watch too closely, so it’s basically an “honor system.” While I do believe GT bottles contain delicious, raw, beneficial kombucha, I’m suspicious of the details. Here’s why: (1) They are unique among their competitors to claim the presence of B vitamins and glucuronic acid, and they list the quantities in precise amounts. If kombucha was a manufactured product where these items were added in measured amounts, it would be easy to quantify. Fermentation, however, embodies change. Every batch is different, and it also changes in the bottle as it continues to ferment on the shelf. Is it a coincidence that the numbers they claim match the myths behind kombucha, rather than the lab reports? If kombucha actually contains these things, why aren’t other brands including them on their labels? (2) Many GT bottles claim to have only 2 grams of sugar per 8 ounce serving, yet they still taste a little sweet. This is where you need to ask yourself: where is that sweetness coming from? The label shows the total carbohydrate as 7 grams per serving, leaving 5 grams that has to be either starch, fiber, sugar alcohols or other additives. There is no starch or fiber in kombucha, so are there sugar alcohols added for sweetness, that aren’t listed on the label? Or is there simply more sugar than they say? Let’s compare their label to their raw competitors with a similar flavor profile: Reeds and Buchi both acknowledge 11 grams of sugar per 8 oz. serving, which is much more realistic. (3) Next, look at GT Original’s ingredient list. It simply says: 100% G.T.’s Organic Raw Kombucha (Organically Produced), and 100% Pure Love!!! Obviously that isn’t fulfilling any kind of legal labeling requirement. By contrast, here’s how Reeds lists their kombucha ingredients: Live organic Kombucha (spring water, organic cane sugar, organic oolong tea, organic yerba mate tea, kombucha culture). (4) This year, the kombucha industry formed a new organization: Kombucha Brewers International. One of its primary goals is to standardize labeling, because GT’s competitors are at a disadvantage. Consumers often choose GT, thinking it has more benefit and less sugar than other brands, when that isn’t necessarily true. Brand loyalty is an interesting phenomenon. It inspires almost a blind trust, but it’s important to remember that GT is a multi-million dollar company, and they make decisions with profit in mind. I’m not anti-GT. I believe they make quality kombucha, and I have bought it myself. But when it comes to the kombucha contents, I trust science over marketing labels. Update 2017: GT has settled a class action lawsuit about inaccurate labeling. As part of the settlement, they agreed to change their labeling to show accurate sugar content and remove claims of antioxidants. In checking my local store shelves, I see that most bottles now show an average of 6 grams of sugar per serving (with 2 servings per bottle), and B vitamins are no longer listed. 


Now, you know what’s true and what’s not. Leaving the myths behind, this traditional fermented beverage can still be a wonderful health tonic. We don’t need exaggerated claims, and we don’t even need to know how it works (although we’ll keep searching). Paleo guru Mark Sisson talks a lot about the N=1 (an experiment of one). That simply means that you try something yourself, and see if adds to, or detracts from, your health. Paleo leaders Dr. Terry Wahls and Robb Wolf drink kombucha themselves. Robyn Latimer, who put her lupus into remission through the paleo diet, also drinks it daily. Dr. Natasha Campbell-McBride recommends it for the Full GAPS Diet. Her only caveat is that people should avoid it on the more restricted Introduction Diet due to the fluctuating sugar content. Dr. Sarah Ballantyne allows it on the Paleo Autoimmune Protocol, because fermented foods like kombucha offer so many potential health benefits. My next post will tell you everything you need to make a successful brew, and my final post in this series will give you the recipes. Stay tuned!

The following websites were very helpful in my research:

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